A three-dimensional extended finite element method (X-FEM) coupled with a narrow band fast marching method (FMM) is developed and implemented in the Abaqus finite element package for curvilinear fatigue crack growth and life prediction analysis of metallic structures. Given the level set representation of arbitrary crack geometry, the narrow band FMM provides an efficient way to update the leve...

There has been a renewed interest of late in the mechanisms responsible for the in ̄uence of the load ratio, R, and the maximum stress intensity, Kmax, on the threshold for fatigue-crack growth, DKth. While mechanistic explanations in the past have largely focused on the role of crack closure, it is certainly not the only mechanism by which Kmax in ̄uences DKth. In this work, we examine the e€ect...

present work shows the numerical determination of fatigue crack opening and closure stress intensity factors of a C(T) specimen under variable amplitude loading using a finite element method. A half compact tension C(T) specimen, assuming plane stress constraint was used by finite element method covering the effects in two-dimensional (2D) small scale yielding models of fatigue crack growth und...

Abstract: Cracks in solids can be detected by ultrasound if they are open. However, their detection is not easy when they are closed with a closure stress, and it is a fundamental problem in ultrasonic testing. Subharmonics with half the input frequency is potentially useful in the detection and evaluation of such cracks. We developed analytical and numerical theories accounting for the crack p...

Crack propagation modeling in quasi-brittle materials such as concrete is essential for improving the reliability and load-bearing capacity assessment. Crack propagation explains many failure characteristics of concrete structures using the fracture mechanics approach. This approach could better explain the softening behavior of concrete structures. A great effort has been made in developing nu...

ion of Models of Stress Corrosion Cracking of Drip Shield and Waste Package Outer Barrier and Hydrogen Induced Corrosion of Drip Shield TABLE OF CONTENTS Page 1. PU R P O SE ............................................................................................................................... 8 2. QUALITY ASSURANCE .............................................. 8 3. COMPUTER SOFTWARE AN...

This paper describes a combined fracture–plastic model for concrete. Tension is handled by a fracture model, based on the classical orthotropic smeared crack formulation and the crack band approach. It employs the Rankine failure criterion, exponential softening, and it can be used as a rotated or a fixed crack model. The plasticity model for concrete in compression is based on the Menétrey–Wil...

To better understand the relationship between the nucleation and growth of defects and the local stresses and phase changes that cause them, we need both imaging and stress mapping. Here, we explore how this can be achieved by bringing together synchrotron X-ray diffraction and tomographic imaging. Conventionally, these are undertaken on separate synchrotron beamlines; however, instruments capa...